Inductively coupled plasma (ICP) sources can have RF currents flowing along concentric inner and outer coils to inductively couple RF energy into a process gas to form a plasma in a process chamber. The power division between the inner and the outer coil can be controlled by varying the value of a power divider that rations RF power to each coil. For example, the value of the power divider can dictate the power division between the two coils which can result in different on-wafer process performance to control center-to-edge uniformity. Unfortunately, due to variations that may occur in the coils tolerances, RF matching networks components calibrations, or ICP source, the setpoint value of the power divider at the user interface of the process chamber may not provide the intended actual value of, for example, a desired current ratio between the inner and outer coils. Further, variations in chamber components can cause wafer-to-wafer and chamber-to-chamber process variations.
Therefore, the inventors have provided embodiments of methods for calibrating RF power applied to a plurality of RF coils of a process chamber.